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unknown JTL Unit 36 and 38 Revision Quiz on Unit 38 Multiple Choice Revision, created by giannini.chambers on 15/04/2015.

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Unit 38 Multiple Choice Revision

Question 1 of 31

1

What does Cg relate to in cable calculations?

Select one of the following:

  • Grouping factor

  • Ambient temperature

  • Insulation factor

  • Burred depth factors

Explanation

Question 2 of 31

1

Zs=

Select one of the following:

  • R1+R2

  • Ze+R1

  • External loop impedance

  • Earth fault loop impedance

Explanation

Question 3 of 31

1

When calculating maximum Zs for a circuit design what is the 1.2 multiplier used to account for?

Select one of the following:

  • Increase in conductor temperature

  • Human error in measurement

  • Decrease in earth fault current

  • Parallel paths

Explanation

Question 4 of 31

1

What is the maximum permissible voltage drop for lighting in a final circuit?

Select one of the following:

  • 2.5%

  • 5%

  • 3%

  • It depends on the starting voltage

Explanation

Question 5 of 31

1

What is the formula for voltage drop?

Select one of the following:

  • (Ib x Length x mV/A/m)/1000

  • Ib x Length x mV/A/m

  • (In x Length x mV/A/m)/1000

  • In x Length x mV/A/m

Explanation

Question 6 of 31

1

What does In stand for?

Select one of the following:

  • Nominal current rating of the protective device

  • Design curent

  • Ingress notation

  • Notional current

Explanation

Question 7 of 31

1

If an RCD is to be for additional protection, how many tests should be carried out on it?

Select one of the following:

  • 6

  • 4

  • 3

  • 5

Explanation

Question 8 of 31

1

What is the rated current for an RCD that is to be used as additional protection?

Select one of the following:

  • 30mA

  • 50mA

  • 300mA

  • 30A

Explanation

Question 9 of 31

1

What does maintenance factor in lighting design relate to?

Select one of the following:

  • The cleanliness of the room

  • The cleanliness of the lamps

  • The lamp deterioration

  • All of the above

Explanation

Question 10 of 31

1

Which out of the following relate to utilisation factor?

Select one of the following:

  • Reflectance values of the ceiling, wall and floor

  • How often people are using a room

  • How often the lights are left on when people have left

  • The floor area of the room being lit

Explanation

Question 11 of 31

1

A room is to be illuminated to 350 lux. The maintenance factor is 0.85, utilisation factor is 0.8 and the room measures 6m by 8m. Calculate the number of fittings required if each fitting is 100W and has an efficacy of 70 lumens/watt.

Select one of the following:

  • 10

  • 6

  • 4

  • 3

Explanation

Question 12 of 31

1

What maintenance should be carried out on a motor to ensure correct working:

Select one or more of the following:

  • Continuity of windings

  • Insulation resistance of the windings

  • Insulation resistance between the windings and the case

  • Changing of bearings

  • Cleaning of luminaires in room

  • Varnishing of shaft

  • Monthly rotation of end plates

Explanation

Question 13 of 31

1

What types of earthing rely on the distributor's earthing arrangement?

Select one or more of the following:

  • TT

  • TNCS

  • TNS

Explanation

Question 14 of 31

1

How may PFC be obtained?

Select one of the following:

  • Calculation, enquiry and measurement

  • Enquiry and measurement

  • Measurement only

  • Enquiry only

Explanation

Question 15 of 31

1

What earthing system has a combined earth and neutral conductor back to the transformer?

Select one of the following:

  • TNCS

  • TT

  • IT

  • TNS

Explanation

Question 16 of 31

1

What is the maximum permitted voltage drop for a final power circuit?

Select one of the following:

  • 3%

  • 5%

  • 2%

  • 9%

Explanation

Question 17 of 31

1

A fault of negligible impedance between a live conductor and earth is known as?

Select one of the following:

  • PSCC

  • PEFC

  • PC

  • PEEC

Explanation

Question 18 of 31

1

How can earth fault loop impedance relate to the disconnection time of a circuit breaker?

Select one of the following:

  • Zs relates to fault current

  • Zs relates to RCD operating time

  • Zs relates to nominal voltage

  • Zs relates to full load current of the circuit

Explanation

Question 19 of 31

1

It is acceptable to run single core cables on metal tray

Select one of the following:

  • True
  • False

Explanation

Question 20 of 31

1

It is acceptable to run single core cables in metal trunking

Select one of the following:

  • True
  • False

Explanation

Question 21 of 31

1

What is the most suitable containment method for an outside motor to be connected to the electrical supply?

Select one of the following:

  • SWA

  • Metal conduit

  • Metal trunking

  • Cable basket

Explanation

Question 22 of 31

1

What does Ci relate to in cable calculations?

Select one of the following:

  • Thermal insulation

  • Above ordinary current

  • Initial load current

  • Installation

Explanation

Question 23 of 31

1

An installation with a nominal voltage of 230V has an external loop impedance of 0.2Ω and an external line to neutral voltage of 0.18Ω. What would the PFC be recorded on the test certificate?

Select one of the following:

  • 1150A

  • 1278A

  • 2kA

  • 1.8kA

Explanation

Question 24 of 31

1

When measuring PSSC the earth should be removed from the installation.

Select one of the following:

  • True
  • False

Explanation

Question 25 of 31

1

When measuring PEFC your terminals will be connected between line, neutral and the earth bar.

Select one of the following:

  • True
  • False

Explanation

Question 26 of 31

1

Single phase circuit is run in trunking with 3 other circuits. The ambient temperature for the room is 35° . The design current is 33A and the protective device an MCB to BS 60898. What is the minimum size 70° single-core thermoplastic cable that can be used taking into account current carrying capacity only?

Select one of the following:

  • 6mm²

  • 10mm²

  • 16mm²

  • 25mm²

Explanation

Question 27 of 31

1

There are 7 x 10mm², 5 x 6mm², 4 x 25mm² and 8 x 2.5mm² single phase circuits to be installed in trunking. Calculate the size required if all cables are PVC BS 6004 cables.

Select one of the following:

  • 50mm x 50mm

  • 75mm x 50mm

  • 75mm x 75mm

  • 100 x 75mm

Explanation

Question 28 of 31

1

A 5m run of conduit with 2 bends in it is to accommodate 2 ring final circuits of 2.5mm². Calculate the minimum size conduit to be used.

Select one of the following:

  • 32mm

  • 25mm

  • 20mm

  • 16mm

Explanation

Question 29 of 31

1

Electrocution doesn't always result in death

Select one of the following:

  • True
  • False

Explanation

Question 30 of 31

1

Which of the following should be included in a risk assessment

Select one or more of the following:

  • Details of the hazard/risk

  • Control measures to be applied

  • Applicable standards to the risk assessment

  • The evaluation of the risks

  • Dates of review

  • Company financial information

  • Serial numbers of PPE equipment

  • Time sheets

  • The address of all contributors to the risk assessment

Explanation

Question 31 of 31

1

A store room must be illuminated to 200 lux. The size of the room is 9m x 10m, the room is kept fairly clean (M.F of 0.9) and due to god colour management and space ratios the U.F is 0.9. Calculate how many light fittings are to be used if each fitting contains 2 lamps of 2000 lumens each.

Select one of the following:

  • 3

  • 4

  • 5

  • 6

  • 7

Explanation

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